Jan Panteltje wrote:
So we ask him again: What values did you enter, and what dielectric constant
for the PCB material and 'tape'.

You are getting to be a real pain in the keyster... LOL

I use 0.062" 1oz FR4 for my designs.
The dielectric constant of FR4 is about 4.6
Thickness of 1oz copper is about 0.0014"

So with a ground plane on one side of the board... the width of the
trace to maintain a 50 Ohm characteristic impedance is about 0.113"
wide.

P.S. Have no idea what tape you're talking about...

www.telstar-electronics.com

On Sun, 24 Sep 2006 21:21:26 GMT, Jan Panteltje
wrote in :

On a sunny day (Sun, 24 Sep 2006 16:50:55 -0400) it happened "Jimmie D"
wrote in
:


"Jan Panteltje" wrote in message
...
On a sunny day (24 Sep 2006 10:03:00 -0700) it happened "Telstar
Electronics"
wrote in
. com:

Jan Panteltje wrote:
At 27MHz 50Ohm this is not critical.

Huh???? Since when is impedance matching at RF frequencies not
important? Then maybe you could tell us at what frequency it is
important... LOL

You really have no experience now have you?
First the little PCBs just form some extra capacitance to ground.
There is no transmission line.
And you may need that anyways, why else solder those caps over your
output transformer.
Second, for a transmission line L and C are important, and L is close
to zero here, and f is very low.
The 'length' of the track is very very short in their design.
You can hardly speak of a transmission line at all at 27MHz.
Not a significant part of the wavelength anyways.
'Transmission line' properly matched only implies no refections
and some known impedance after all.
And where is this 'line'?

You mentioned that calculator, but did you ever use it?
If so what did you enter for the constants?

Obviously you kneel before the SWR gods. You dont have to have a transmision
line to have a matching problem. Matching means to have the output impedance
of a driving stage equal to the input impedance of a driven stage so maximum
power is transfered with minimum distortion. Nothing was said of
transmission lines or SWR.

Oh I am not questioning 'impedance matching', but some points.
1) He refers to that calculator, that also asks for a track length and
load capacitance. In case of distribited loads, and there are of course.
So we need his numbers.

2) The impedance is complex, not simple 'Ohm', and in this case nearly
100% a capacitance, basically the same (leaving out the extra value of the
tape or glue), as between a top and bottom PCB layer, you take the surface
area, and get a capacitance, it is almost a square 'pad' they use (see
pictures) not a stripline! (and so no transmission line with separate
in and outputs either).

So we ask him again: What values did you enter, and what dielectric constant
for the PCB material and 'tape'.
snip


I see everyone is reverting back to one of the major pitfalls of
single-board amps: soldering high-power devices right to copper-clad
board. My intent was to AVOID this by using solid copper strap, but
it's clear that people are determined to use the cheapest materials
possible. Therefore.....

I'm going to eliminate soldering of the power transistors completely.
They will be 'wired' using 304 stainless CLAMPS secured to the chassis
with teflon standoffs. These clamps will not only provide a much
stronger mechanical connection, but will also, in conjunction with the
gold-plated flags, eliminate ANY possibility of corrosion in damp
(spilled coffee) environments. They will also permit removal of the
transistors without de-soldering, prevent heat damage due to some big
dummy that solders with an arc welder, and help to -dissipate- heat
during normal (and overdriven) operation.

As for cost, the prototype can be cut from a standard beer keg, and in
mass production they will cost only a few cents each.

Now that -this- aspect of the design has been finalized, it's time to
move along.

On a sunny day (24 Sep 2006 16:47:45 -0700) it happened "Telstar Electronics"
wrote in
. com:

Jan Panteltje wrote:
So we ask him again: What values did you enter, and what dielectric constant
for the PCB material and 'tape'.

You are getting to be a real pain in the keyster... LOL

We wil get you to publish the diagram too ...:-)

I use 0.062" 1oz FR4 for my designs.
The dielectric constant of FR4 is about 4.6
Thickness of 1oz copper is about 0.0014"

So with a ground plane on one side of the board... the width of the
trace to maintain a 50 Ohm characteristic impedance is about 0.113"
wide.

OK, now you have a 50 Ohm track, and *where* do you put it?
The only place you could possible use it is to the output connector,
and that connection happens to be a *wire*.

Have a look at those pictures again, the extra PCBs you were _originally_
referring to as needing that website calculator, are just simple solderpads.
The rest is normal wiring.

P.S. Have no idea what tape you're talking about...

The double sided tape you accused them of using to glue on those extra boards
that are used as solder pads.

And, I have to say that .113 inch equals around 3mm width.. your transistor
connections and the stuff they are soldered to on your board are wider..

But you score on one point, you caused 2 more posts on the subject of
'Telstar amp'.

You can score a *lot more* reactions by publishing the diagram, people
will have questions and suggestions and maybe even [positive] critism
if you do.
So let's have it OK?
You are no chicken to show it no? It is free of flaws I am sure?
Come on Brian, it is not THAT different from the appication notes now is it?

On a sunny day (Sun, 24 Sep 2006 21:27:16 -0700) it happened Frank Gilliland
wrote in
:

These clamps will not only provide a much
stronger mechanical connection, but will also, in conjunction with the
gold-plated flags, eliminate ANY possibility of corrosion in damp
(spilled coffee) environments.

I have a satellite dish motor (outside), opened it up, they have immersed
the PCB in wax (parrafine?) to make it corrosion proof.
It is just a very thin layer that covers all components.
Seems to work.
Even though I pricked the scope through it at some points to measure things.
:-)

Jan Panteltje wrote:
P.S. Have no idea what tape you're talking about...

The double sided tape you accused them of using to glue on those extra boards
that are used as solder pads.

What about it... You know I don't use that approach on my designs...
that method is reserved for all the great amplifier manufacturer's like
DaveMade and Xforce... LOL

www.telstar-electronics.com

On Mon, 25 Sep 2006 09:58:47 GMT, Jan Panteltje
wrote:

+++On a sunny day (Sun, 24 Sep 2006 21:27:16 -0700) it happened Frank Gilliland
wrote in
:
+++
+++These clamps will not only provide a much
+++stronger mechanical connection, but will also, in conjunction with the
+++gold-plated flags, eliminate ANY possibility of corrosion in damp
+++(spilled coffee) environments.
+++
+++I have a satellite dish motor (outside), opened it up, they have immersed
+++the PCB in wax (parrafine?) to make it corrosion proof.
+++It is just a very thin layer that covers all components.
+++Seems to work.
+++Even though I pricked the scope through it at some points to measure things.
+++:-)
*****************

More like a conformal coat material other than parafine wax. That
stuff is to flammable to screw with when in liquid form. There are
numerous coatings for printed wire boards that can be used. They range
from clear to opaque. Some are soft and maliable to hard and not so
easy to remove.

These DO NOT offer a hermetic seal and can allow moisture into the
printed wire board. Only hermetic seal would be to place the board in
a solder sealed box that may or maynot contain a inert gas inside.

james

"Jan Panteltje" wrote in message
...
On a sunny day (24 Sep 2006 16:47:45 -0700) it happened "Telstar
Electronics"
wrote in
. com:

Jan Panteltje wrote:
So we ask him again: What values did you enter, and what dielectric
constant
for the PCB material and 'tape'.

You are getting to be a real pain in the keyster... LOL

We wil get you to publish the diagram too ...:-)

I use 0.062" 1oz FR4 for my designs.
The dielectric constant of FR4 is about 4.6
Thickness of 1oz copper is about 0.0014"

So with a ground plane on one side of the board... the width of the
trace to maintain a 50 Ohm characteristic impedance is about 0.113"
wide.

OK, now you have a 50 Ohm track, and *where* do you put it?
The only place you could possible use it is to the output connector,
and that connection happens to be a *wire*.

Have a look at those pictures again, the extra PCBs you were _originally_
referring to as needing that website calculator, are just simple
solderpads.
The rest is normal wiring.

P.S. Have no idea what tape you're talking about...

The double sided tape you accused them of using to glue on those extra
boards
that are used as solder pads.

And, I have to say that .113 inch equals around 3mm width.. your
transistor
connections and the stuff they are soldered to on your board are wider..

But you score on one point, you caused 2 more posts on the subject of
'Telstar amp'.

You can score a *lot more* reactions by publishing the diagram, people
will have questions and suggestions and maybe even [positive] critism
if you do.
So let's have it OK?
You are no chicken to show it no? It is free of flaws I am sure?
Come on Brian, it is not THAT different from the appication notes now is
it?



I have to agree that 50 ohm striplines are useless in an amp like this, it
is only important that the output impedance of the driver stages match the
driven stage. I cant see how you could do this with striplines on a
broadband amp at HF. There is already proven interstage design. NEW and
IMPROVED means new and improved over 30 year old technology. Bring CB amps
up to current technology would mean only advancing them about 10 or 15 years
from the 70s . Even in the 70s it was well known how to build a decent amp
but this is not what the CB market wanted then or now. As far as other
markets are concerned it is already very crowded and difficult to get ones
foot in the door.

Jan Panteltje wrote:
And, I have to say that .113 inch equals around 3mm width.. your transistor
connections and the stuff they are soldered to on your board are wider..

You are correct on the existing design. However, the new amp does
utilize impedance matched input and output traces on the PCB.

http://auctions.yahoo.com/i:SkyWave%...fier:117239910

On a sunny day (25 Sep 2006 13:36:19 -0700) it happened "Telstar Electronics"
wrote in
.com:

Jan Panteltje wrote:
And, I have to say that .113 inch equals around 3mm width.. your transistor
connections and the stuff they are soldered to on your board are wider..

You are correct on the existing design. However, the new amp does
utilize impedance matched input and output traces on the PCB.

Well, I mentioned that it does not make a lot of difference at 27MHz,
the 50 Ohm part would be from the input PL259 to pre-amp or transformer or
whatever, and the other 50 Ohm part from the output of the Pi filter to
the output PL259, and in most cases these will be wires...
If you were to be consequent, then you would have to make the collector and
base match those relevant impedances too, and any outer part of the circuit.
The distances are so short however that this is not practical.
From the driver transformer to the bases, from the collectors to the output
transformer, and all different impedances at that.
Better keep these collector traces wide so they function as cooling and have
low resistance!
I am not sure anybody bothers with those impedances.
On the Ranger PCB double sided (you can get the layouts, click on the link top
left in the PCB component drawing) for example, there is a about 2 cm long track
from the output of the Pi filter to the relay, with _on_the_other_side_ of the
board a parallel track that is the SWR meter tap!
(The layout is mirrored, you have to flip it in thought to see that).
So even there they do not bother, but simply play transformer.
In the relay itself it is lost completely (the 50 Ohms) I suspect.
It is better to fix those things that really make a difference, good
Pi filter, good output stage matching to the 50 Ohm connector, SWR protection,
temp protection, perhaps drive control.
Funy LCD display, LEDS, reset button, build in mp3 player, toaster, alarm clock,
the works.
I should write LOL, but hey, it is true, anything has a mp3 player these days,
even my video camera.
If they just had used a better lens, and left out the player....
OK, marketing... give people what they want, they want the LCD.
Blue LEDS, orange LEDS.... all that.

I have to agree that 50 ohm striplines are useless in an amp like this, it
is only important that the output impedance of the driver stages match the
driven stage.

Matching is always important for maximum power transfer. Why do you
think it's any less important in an amp such as this???

http://auctions.yahoo.com/i:SkyWave%...fier:117239910